# Piezometer: An Effective Measuring Tool

Posted by PCTE on August 3rd, 2015

UPV or ultrasonic pulse velocity is a testing method for concrete materials, which uses the pulse velocity method in order to determine the uniformity of concrete, its cracks, cavities, and defects. Pulse velocity within a material is dependent on its elastic properties and its density -qualities, which are closely related to the compressive strength and the overall quality of concrete. Because of this, it is possible to obtain data about the properties of a material's components through sonic investigations.

This particular test is done to assess concrete quality using the UPV method as per the IS: 13311. Its underlying principle is based on the theory that comparatively high velocity is obtained when concrete is of higher quality in terms of uniformity, density, homogeneity and other determining characteristics. The method involves measuring time of travel of ultrasonic pulses passing through concrete.

UPV is a non-destructive or non-invasive measuring technique that determines material integrity, structure, components, and characteristics. It is also a rapid technique that doesn't need complex calculations or long wait times to return results.  Commonly used in high risk areas like sea shore structures, nuclear environments, and gas/oil pipelines, this non-destructive test is a good alternative when rebound testing is not possible or is in appropriate.

Ultrasonic wave velocities are directly proportional to the modulus of elasticity (density) of a material. Using this principle, it can be concluded that there is direct empirical relations between the elasticity modulus of concrete (E) and its compressive strength (f’c). If the velocity of ultrasonic waves through concrete is measured, it is easy to determine the compressive strength of the material.

Depending on the placement of transducers used to measure ultrasonic pulses, there are three testing methods based on the UPV principle:

• The direct method is when two transducers are placed opposite each other (one on both ends) throughout the member.
• The indirect method involves both transducers placed on the same surface. Here, the receiver accepts pulse coming after hitting or striking the concrete molecules.
• The semi direct method on the other hand, is used for testing corners of concrete members.

To perform a UPV test, you will need an electrical pulse generator, a transducer, and an amplifier electronic timing device, along with a calibration cylinder that is set to the required standard. UPV offers great benefits over other testing methods mainly because of its high penetrating power, which not only ensures easy measurement, but accurate findings even for very deep concrete members.